package com.base.commonlib.utils;

import android.database.Cursor;
import android.text.TextUtils;
import android.util.Log;

import com.base.commonlib.bean.DaoMaster;

import org.greenrobot.greendao.AbstractDao;
import org.greenrobot.greendao.database.Database;
import org.greenrobot.greendao.internal.DaoConfig;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class MigrationHelper {

    private static final String CONVERSION_CLASS_NOT_FOUND_EXCEPTION = "MIGRATION HELPER - CLASS DOESN'T MATCH WITH THE CURRENT PARAMETERS";

    private static MigrationHelper instance;

    public static MigrationHelper getInstance() {

        if (instance == null) {

            instance = new MigrationHelper();

        }

        return instance;

    }

    private static List<String> getColumns(Database db, String tableName) {

        List<String> columns = new ArrayList<>();

        Cursor cursor = null;

        try {

            cursor = db.rawQuery("SELECT * FROM " + tableName + " limit 1", null);

            if (cursor != null) {

                columns = new ArrayList<>(Arrays.asList(cursor.getColumnNames()));

            }

        } catch (Exception e) {

            Log.v(tableName, e.getMessage(), e);

            e.printStackTrace();

        } finally {

            if (cursor != null)

                cursor.close();

        }

        return columns;

    }

    public void migrate(Database db, Class<? extends AbstractDao<?, ?>>... daoClasses) {

        generateTempTables(db, daoClasses);

        DaoMaster.dropAllTables(db, true);

        DaoMaster.createAllTables(db, false);

        restoreData(db, daoClasses);

    }

    private void generateTempTables(Database db, Class<? extends AbstractDao<?, ?>>... daoClasses) {

        for (int i = 0; i < daoClasses.length; i++) {

            DaoConfig daoConfig = new DaoConfig(db, daoClasses[i]);

            String divider = "";

            String tableName = daoConfig.tablename;

            String tempTableName = daoConfig.tablename.concat("_TEMP");

            ArrayList<String> properties = new ArrayList<>();

            StringBuilder createTableStringBuilder = new StringBuilder();

            createTableStringBuilder.append("CREATE TABLE ").append(tempTableName).append(" (");

            for (int j = 0; j < daoConfig.properties.length; j++) {

                String columnName = daoConfig.properties[j].columnName;

                if (getColumns(db, tableName).contains(columnName)) {

                    properties.add(columnName);

                    String type = null;

                    try {

                        type = getTypeByClass(daoConfig.properties[j].type);

                    } catch (Exception exception) {

                        exception.printStackTrace();

                    }

                    createTableStringBuilder.append(divider).append(columnName).append(" ").append(type);

                    if (daoConfig.properties[j].primaryKey) {

                        createTableStringBuilder.append(" PRIMARY KEY");

                    }

                    divider = ",";

                }

            }

            createTableStringBuilder.append(");");

            Log.i("lxq", "创建临时表的SQL语句： " + createTableStringBuilder.toString());

            db.execSQL(createTableStringBuilder.toString());

            StringBuilder insertTableStringBuilder = new StringBuilder();

            insertTableStringBuilder.append("INSERT INTO ").append(tempTableName).append(" (");

            insertTableStringBuilder.append(TextUtils.join(",", properties));

            insertTableStringBuilder.append(") SELECT ");

            insertTableStringBuilder.append(TextUtils.join(",", properties));

            insertTableStringBuilder.append(" FROM ").append(tableName).append(";");

            Log.i("lxq", "在临时表插入数据的SQL语句：" + insertTableStringBuilder.toString());

            db.execSQL(insertTableStringBuilder.toString());

        }

    }

    private void restoreData(Database db, Class<? extends AbstractDao<?, ?>>... daoClasses) {

        for (int i = 0; i < daoClasses.length; i++) {

            DaoConfig daoConfig = new DaoConfig(db, daoClasses[i]);

            String tableName = daoConfig.tablename;

            String tempTableName = daoConfig.tablename.concat("_TEMP");

            ArrayList<String> properties = new ArrayList();

            ArrayList<String> propertiesQuery = new ArrayList();

            for (int j = 0; j < daoConfig.properties.length; j++) {

                String columnName = daoConfig.properties[j].columnName;

                if (getColumns(db, tempTableName).contains(columnName)) {

                    properties.add(columnName);

                    propertiesQuery.add(columnName);

                } else {

                    try {

                        if (getTypeByClass(daoConfig.properties[j].type).equals("INTEGER")) {

                            propertiesQuery.add("0 as " + columnName);

                            properties.add(columnName);

                        }

                    } catch (Exception e) {

                        e.printStackTrace();

                    }

                }

            }

            StringBuilder insertTableStringBuilder = new StringBuilder();

            insertTableStringBuilder.append("INSERT INTO ").append(tableName).append(" (");

            insertTableStringBuilder.append(TextUtils.join(",", properties));

            insertTableStringBuilder.append(") SELECT ");

            insertTableStringBuilder.append(TextUtils.join(",", propertiesQuery));

            insertTableStringBuilder.append(" FROM ").append(tempTableName).append(";");

            StringBuilder dropTableStringBuilder = new StringBuilder();

            dropTableStringBuilder.append("DROP TABLE ").append(tempTableName);

            Log.i("lxq", "插入正式表的SQL语句：" + insertTableStringBuilder.toString());

            Log.i("lxq", "销毁临时表的SQL语句：" + dropTableStringBuilder.toString());

            db.execSQL(insertTableStringBuilder.toString());

            db.execSQL(dropTableStringBuilder.toString());

        }

    }

    private String getTypeByClass(Class<?> type) throws Exception {

        if (type.equals(String.class)) {

            return "TEXT";

        }

        if (type.equals(Long.class) || type.equals(Integer.class) || type.equals(long.class) || type.equals(int.class)) {

            return "INTEGER";

        }

        if (type.equals(Boolean.class) || type.equals(boolean.class)) {

            return "BOOLEAN";

        }

        Exception exception = new Exception(CONVERSION_CLASS_NOT_FOUND_EXCEPTION.concat(" - Class: ").concat(type.toString()));

        exception.printStackTrace();

        throw exception;

    }


}
